A SYSTEM AND METHOD FOR CONTROLLING INCOMING TRAFFIC IN TELECOMMUNICATION NETWORKS
Technical Field
The present invention is basically related to a system and method for controlling the incoming traffic in telecommunications network.
Background of the Invention
Termination of international traffic on a telecommunications network is always more expensive than terminating local traffic in all over the world. In a telecommunications network some local carriers or service providers can terminate international traffic as if it is coming from local link by changing the calling number or other parameters. This causes revenue loss and infringes the international agreements and regulations.
To overcome this problem, a solution which allows controlling incoming traffic and checking it regarding to predefined rules to detect illegal traffic terminations and taking necessary actions is needed. Such a solution will allow mobile operators to terminate incoming calls as stated in international agreements and regulations and prevent revenue loss. Although it is not limited to network types and protocols, said controlling mechanism can be used in a GSM network with CAMEL feature. Required information about CAMEL, network elements, concepts etc. to understand the background of invention is as follows:
Customized Applications for Mobile networks Enhanced Logic, or CAMEL for short, is a set of standards designed to work on either a GSM (Global System for Mobile Communications) core network or UMTS (Universal Mobile Telecommunications System) network. They allow an operator to define services over and above standard GSM services/UMTS services. The CAMEL architecture is based on the Intelligent Network (EST) standards, and uses the CAP (CAMEL Application Part) protocol. Many services can be created using CAMEL, and it is particularly effective in allowing these services to be offered when a subscriber is roaming, like, for instance, prepaid charging, no-prefix dialing (the number the user dials is the same no matter the country where the call is placed) or seamless MMS (Multimedia Messaging Service) message access from abroad.
When a call request is received by a network, it is terminated by using signaling links. These signaling links can be using ISUP (ISDN User Part), SIP-T (Session Initiation Protocol for Telephones) etc. A call request can be processed by a gateway exchange (such as Gateway Mobile Switching Center - GMSC) in a network with CAMEL. When a call is processed by an exchange, the call goes through a number of pre-defined phases. These phases of the call are described in the BCSM (Basic call state model). There are two types of BCSM in CAMEL for controlling voice calls:
O-BCSM, which is related for call origination of a CAMEL subscriber T-BCSM, which is related for call terminating calls of a CAMEL subscriber
The problem in the background of this invention is related with T-BCSM.
The BCSM contains detection points (DP) and points in call (PIC). The PIC indicates the state of the call, i.e. analysis, routing, alerting and active. A DP is associated with a state transition. When the call reaches a certain PIC, the BCSM first processes the DP that is associated with the transition to that PIC, e.g. when the call is in the alerting phase and an answer event is received over ISUP, the BCSM processes the DP that is associated with the answer event. After the processing of the DP is complete, the BCSM transits to the active PIC. One of the important DPs for understanding the background of this invention is TDP-12. Triggering of the control node which may act as a solution to said problem is based on providing TDP-12 on the incoming signaling link. By this way, all incoming calls from that link will be triggered to the call control node and continue regarding to the responses of this node.
Another important concept for understanding the problem in the background of this invention is the Mobile Application Part (MAP) which is an SS7 protocol and provides an application layer for the various nodes in GSM and UMTS mobile core networks and GPRS core networks to communicate with each other in order to provide services to mobile phone users. The Mobile Application Part is the application-layer protocol used to access the Home Location Register, Visitor Location Register, Mobile Switching Center, Equipment Identity Register, Authentication Centre, Short message service center and Serving GPRS Support Node (SGSN).
This invention the problem in the background of this invention is also related to AnyTimelnterrogation operation of MAP protocol. The international patent document no. WO1997036431, an application in the state of the art, discloses an invention which relates to a method for controlling a call attempt by employing an intelligent network. The method comprises the steps of (a) processing the call attempt according to the originating half BCSM (O-BCSM) at a first point (SSP A) having a service switching function (SSF), (b) resuming the processing of the call attempt according to the terminating half BCSM (T- BCSM) at a second point (SSP B) with a service switching function (SSF), and (c) providing a service request from the processing that employs T-BCSM to a point (SCP) having a service control function (SCF). In order to be able to offer versatile IN services to the called subscriber as well, the processing of the call attempt is returned to the point employing the O-BCSM, and the processing is resumed according to the O-BCSM.
Summary of the Invention
An objective of the present invention is to control the incoming traffic according to predefined rules in a telecommunications network.
Another objective of the present invention is to detect illegal traffic according to international agreements.
Another objective of the present invention is to prevent revenue loss of a mobile operator caused by some local carriers or service providers which terminate international traffic as if it is coming from local link by changing the calling number or other parameters.
Description of the Invention
"A System and Method for Controlling Incoming Traffic in Telecommunications Network" realized to fulfill the objectives of the present invention is shown in the figures attached, in which:
Figure 1 is a schematic block diagram of the inventive system.
Figure 2 is a flowchart of the inventive method.
The components illustrated in the figures are individually numbered, where the numbers refer to the following:
1. System
2. GMSC (Gateway Mobile Switching Center) 3. ITC (Incoming Traffic Controller)
4. Gateway of operator
5. MNP SRF (Mobile Number Portability Signaling Relay Function)
100. Method
A system (1) which enables controlling incoming traffic in telecommunications network:
at least one GMSC (2) on which the incoming call is terminated, at least one ITC (3) which is invoked based on triggering criteria stored in GMSC (2) after a call is terminated on GMSC (2) and which sends a message to GMSC (2) for appropriate action after checking predefined rules for information related to incoming call,
at least one gateway (4) which belongs to operator sending call requests to GMSC (2) over signaling links,
at least one MNP SRF (5) which is queried by a message sent by ITC (3) to check if the calling number of the call terminated on GMSC (2) actually belongs to mobile operator with the operator code determined by ITC (3) in GSM networks where mobile number portability between mobile operators is enabled (Figure 1).
GMSC (2) is the device on which incoming calls from gateway (4) which belongs to operator sending call requests to GMSC (2) over signaling links are terminated. GMSC stores the triggering criteria for triggering ITC (3) after a call is terminated on it (2).
GMSC (2) is the gateway for the home network where ITC (3) exists and GMSC (2) allows communicating with international carriers and national operators via their respective gateways (4). In preferred embodiment of the invention, links coming from national operators to GMSC (2) are configured to trigger a CAMEL IDP (Initial Detection Point) message to ITC (3) for every call being terminated on GMSC (2). Triggering ITC (3) for an incoming call can be performed by IN (Intelligent Network), CAMEL or SIP (Session Initiation Protocol).
In an embodiment of the invention, triggering of the ITC (3) is based on providing TDP-12 (Trigger Detection Point - 12) on the incoming signaling link in the basic call state model (BCSM). By this way all incoming calls from that link will be triggered to ITC (3) and continue regarding to the responses of this node.
ITC (3) is the controlling device which is invoked by GMSC (2) when triggering criteria stored in GMSC (2) are satisfied and which sends a message to GMSC (2) for appropriate action after checking predefined rules for information related to incoming call. In preferred embodiment of the invention, ITC (3) is triggered by a CAMEL IDP message sent from GMSC (2). ITC (4) provided in the inventive system (1) is adapted to perform operations of:
- receiving triggering message from GMSC (2);
- determining the operator of the calling number from service key field of the triggering message;
- sending a message to query MNP SRF (5) to check if the calling number actually belongs to mobile operator with the operator code determined by ITC (3);
- receiving the result of the query to MNP SRF (5);
- normalizing calling number field in the triggering message;
- checking the predefined rules for the calling number and related operator information to detect illegal traffic termination attempt;
- sending a message to GMSC (2) related to the appropriate action according to the result of the rule checking procedure.
ITC (3) is the component which sends one of the messages below to GMSC (2) for appropriate action after checking the predefined rules for the calling number and related operator information. In preferred embodiment of the invention, these messages are sent CAP (Camel Application Part) signaling protocol.
Continue (CUE) message for continuing call
· Release (REL) message for dropping call
Connect (CON) message for connection call with altered parameters. ITC
(3) may modify one or more than one of the following parameters: destinationRoutingAddress, alertingPattern, originalCalledPartylD, callingPartysCategory, redirectingPartylD, redirectionlnformation, genericNumbers, suppressionOf Announcement, oCSIApplicable (Originating - CAMEL Subscription Information Applicable).
Gateway of operator (4) is the gateway which sends call requests to GMSC (2) over signaling links. In preferred embodiment of the invention call request sent by gateway of operator (4) over ISUP (ISDN User Part) with an IAM (Initial Address Message) message. In another embodiment of the invention, gateway of operator
(4) may send calling request over SIP-T (SIP for Telephones).
MNP SRF (5) is a component which is queried by a message sent by ITC (3) to check if the calling number actually belongs to mobile operator with the operator code determined by ITC (3) in GSM networks where mobile number portability between mobile operators is enabled in the country where system (1) is operating.
In preferred embodiment of the invention, MNP SRF (5) is queried by ITC (3) over MAP (Mobile Application Part) protocol which is an SS7 protocol via a MAP-ATI (Any Time Interrogation) message. Information element supplied to MNP SRF (5) by ITC (3) is the calling number.
MNP SRF (5) is the component which is queried for calling number and returns a mobile number portability result of calling number to ITC (3). In an embodiment of the invention, a local operator network can carry other local traffic belonging to other operator networks. Such operator networks can be pre-configured as sub networks of a network in ITC (3). During query procedure in MNP SRF (5), if the calling number does not belong to mobile operator with the operator code determined by ITC (3), ITC (3) may query MNP SRF (5) according to pre- configured sub networks list of the network.
A method (100) which enables controlling incoming traffic in telecommunications network comprises steps of:
- gateway (4) sending call request to GMSC (2) (101);
- GMSC (2) triggering ITC (3) based on triggering criteria (102);
- ITC (3) determining the operator of the calling number from information in the triggering message (103);
- ITC (3) sending a message to query MNP SRF (5) to check if the calling number actually belongs to mobile operator with the operator code determined by ITC (3) (104);
- ITC (3) receiving the result of the query to MNP SRF (5) (105);
- ITC (3) normalizing calling number field in the triggering message (106);
- ITC (3) checking the predefined rules for the calling number and related operator information to detect illegal traffic termination attempt (107);
- ITC (3) sending a message to GMSC (2) related to the appropriate action according to the result of the rule checking procedure (108)
(Figure 2).
In the inventive method (100), firstly, gateway (4) sends call request to GMSC (2) (101). In preferred embodiment of the invention, call request sent at step 101 is sent as ISUP IAM message. After receiving call request from gateway (4), GMSC (2) triggers ITC (3) based on triggering criteria (102), with an CAP IDP message in an embodiment of the invention. ITC (3) determines the operator of the calling number from information in the triggering message (103) and sends a message, which is a MAP ATI message in one embodiment of the invention, to query MNP SRF (5) to check if the calling number actually belongs to mobile operator with the operator code determined by ITC (3) (104). Then, ITC (3) receives the result of its (3) query, with a MAP ATI - RR (Return Result) message in an embodiment of the invention, to MNP SRF (5) (105). ITC (3) normalizes calling number field in the triggering message (106) and checks the predefined rules for the calling number and related operator information to detect illegal traffic termination attempt (107). Finally, ITC (3) sends a message to GMSC (2) related to the appropriate action according to the result of the rule checking procedure (108). In an embodiment of the invention, messages sent from ITC (3) to GMSC (2) are Continue, Release, Connect messages.
Although inventive system (1) and method (100) are mostly described with mobile communication networks using CAMEL protocol, one skilled in the art may understand that invention can easily be modified for and applied to both fixed and mobile networks and independently from core network technology like NGN (Next-Generation Network) and FMS (IP Multimedia Subsystem).
It is possible to develop various embodiments of the inventive system (1) and method (100), it cannot be limited to examples disclosed herein and it is essentially according to claims.